<template>
   <div>
       <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
           <span class="iconfont header-abs-back">&#xe624;</span>
       </router-link>
       <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
           <router-link to="/">
                <div class="iconfont header-fixed-back">&#xe624;</div>
            </router-link>
           景点详情
       </div>
   </div>
</template>
<script>
export default {
  name: "DetailHeader",
  data() {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    };
  },
  methods: {
    handleScroll() {
      const top = document.documentElement.scrollTop;
      if (top > 50) {
        let opacity = top / 130;
        opacity = opacity > 1 ? 1 : opacity;
        this.opacityStyle = {
          opacity
        };
        this.showAbs = false;
      } else {
        this.showAbs = true;
      }
    }
  },
  activated() {
    window.addEventListener("scroll", this.handleScroll);
  }
};
</script>
<style lang="stylus" scoped>
@import '~styles/varibles.styl';

.header-abs {
    position: absolute;
    left: 0.2rem;
    top: 0.2rem;
    width: 0.6rem;
    height: 0.6rem;
    line-height: 0.6rem;
    text-align: center;
    border-radius: 0.3rem;
    background-color: rgba(0, 0, 0, 0.7);
}

.header-abs-back {
    color: #fff;
}

.header-fixed {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: $headerH;
    line-height: $headerH;
    overflow: hidden;
    text-align: center;
    color: #fff;
    background: $bgColor;
    font-size: 0.32rem;
    z-index: 9;
}

.header-fixed-back {
    position: absolute;
    top: 0;
    left: 0;
    width: 0.64rem;
    text-align: center;
    font-size: 0.4rem;
    color: #fff;
}
</style>
